Yellow Mountain Imports American Mahjong Set, “Rosehill” – 166 Rose-Pink Ridged-Backed Tiles, Racks with Pushers, Pink and Cream Soft Case, Scoring Coins, Dice & Wind Indicator

You will likely need multiple mahjong sets to accommodate the multiple different mahjong variants. For Japanese mahjong, the AMOS Numbers set is a good choice. For American Mah-Jongg, I would pick something like this Yellow Mountain Imports set, with dual-coloured tiles. For other variants, you'd probably want to get a Singaporean or Vietnamese set if you can find them, but if not, one of these Mose Cafolo sets covers most Chinese variants.